Chinese patent application CN200920001857.X discloses an electrical connector, which comprises: a housing formed of an insulative material, a rear part of which is formed with an accommodating cavity, and a front part of which protrudes forwardly to form a tongue; a plurality of terminals which comprise an upper row of terminals and a lower row of terminals respectively mounted to an upper side and a lower side of the tongue, the each terminal has a mating portion, a tail, and a curved portion connected between the mating portion and the tail, the mating portions of the upper row of terminals and the mating portions of the lower row of terminals are mounted to the upper side and the lower side of the tongue, respectively, the tails of the each row of terminals extend out from a lower side of the rear part of the housing and are arranged as two rows (i.e. a front row and a rear row); an outer cage which is mounted to an outer periphery of the housing; and two positioning modules which mounted in the accommodating cavity of the housing and cover outer peripheries of the curved portions of the plurality of terminals, which can effectively prevent the curved portions of the terminals from being bent and contacting with each other to cause a short circuit failure when subjected to an external force. When this electrical connector in the prior art is mated with another mating electrical connector, an engagement is maintained by that a plurality of leaf springs extending inwardly from the outer cage of this electrical connector latch on an outer cage of the mating electrical connector. An engagement force between these two electrical connectors is limited, accidental disengagement easily occurs in an environment that experiences significant noise, vibration and harshness (such as an automobile or in moving machinery). Therefore, it is necessary to improve the engagement structure of the electrical connector in the prior art.